1. Field of the Invention
The present invention relates to a multi-directional input device suitable for use in portable telephones and the like.
2. Description of the Related Art
A conventional multi-directional input device will be described with reference to FIGS. 13 to 15. This multi-directional input device is provided with a shaft 52 disposed at one end of a box-shaped casing member 51 formed of synthetic resin moldings and a rotary electrical element 53 generating an electrical signal of a pulse signal. (rotational quantity signal) attached to the shaft 52.
A driving body 54 formed of synthetic resin moldings and accommodated within the casing member 51 is provided with a pair of supporting walls 54a having a spacing therebetween. Sleeve-like bearings 56 press-fitted into both ends of a roller-like operating member 55 are rotatably attached to the pair of supporting walls 54a so that the operating member 55 is rotatable.
The shaft 52 is inserted into non-circular holes 56a formed in the center of one of the bearings 56, so that the rotary electrical element 53 is operative by the rotation of the shaft 52 via the bearings 56 during the rotation of the operating member 55 while the driving member 54 is movable in the axial direction by using the casing member 51 and the shaft 52 as guides thereof when the operating member 55 is moved in the axial direction.
A sliding type electrical element 58 comprising a variable resistor and having a sliding portion 57 is attached directly beneath the casing member in a pile, so that the sliding portion 57 is inserted into a hole 54b of the driving body 54.
This sliding type electrical element 58 detects positional information in response to the displacement.
First and second driving plates 59 and 60 respectively having rectangular holes 59a and 60a formed at the centers thereof are arranged to be overlaid on each other while the sliding portion 57 is inserted into the holes 59a and 60a.
Between the first driving plate 59 and the casing member 51, a spacer 61 is arranged. Springs 62 and 63 are respectively strung between the first driving plate 59 and the casing member 51 and between the second driving plate 60 and the casing member 51 to thereby pull the sliding portion 57 in the neutral state.
Next, operation of such a conventional multi-directional input device will be described. When the operating member 55 is moved in the direction of the arrow "X1", the driving member 54 moves against the spring 62 together with the sliding portion 57 and the first driving plate 59 to thereby operate the sliding type electrical element 58; when the operation of the operating member 55 is cancelled from this state, the first driving plate 59, the driving member 54, and the operating member 55 are returned to the original neutral position by the spring 62.
Then when the operating member 55 is moved in the direction of the arrow "X2", the driving member 54 moves against the spring 63 together with the sliding portion 57 and the second driving plate 60 to thereby operate the sliding type electrical element 58; when the operation of the operating member 55 is cancelled from this state, the second driving plate 60, the driving member 54, and the operating member 55 are returned to the original neutral position by the spring 63.
By operating the operating member 55 in the axial direction in such a manner, positional information is detected in response to the displacement so as to determine a frame advancing speed of images or the like.
Next, when the operating member 55 is rotated, the rotary electrical element 53 is operated via the bearings 56 and the shaft 52 so as to generate a rotational quantity signal.
Consequently, frame advance can be performed according to the speed determined by the movement in the axial direction.
In the conventional multi-directional input device, since the sliding type electrical element 58 generating an electrical signal is arranged beneath the casing member 51, there is a problem in that the thickness is increased so that a thin shape is difficult to be achieved.
There is also another problem in that the number of parts is increased because the driving body 54, the first and second driving plates 59 and 60, and two springs 62 and 63 are necessary for operating the sliding type electrical element 58, resulting in the increased cost and low productivity.